Extraction of α-Ketoglutaric Acid from Fermentation Broth by Calcium Precipitation Method

Abstract:

α-Ketoglutaric acid is widely used in food，chemical and pharmaceutical industries as an important organic acid. Fermentative production of α-ketoglutaric acid by Yarrowia lipolytica is currently a competitive method. The accumulation of pyruvic acid is unavoidable during the production of α-ketoglutaric acid by Y. lipolytica. The two keto acids have similar physical and chemical properties，which brings big challenge for the downstream separation process. In this study，effects of three different calcium salts on the separation of keto acids in the fermentation broth were compared. An effective precipitation method was established for the separation of α-ketoglutaric acid from fermentation broth. CaCO ₃ was the optimum precipitant of α-ketoglutaric acid. The recovery and purity rate of α-ketoglutaric acid were 82.5% and 98.89%，respectively. Meanwhile，the precipitation method could not be used for the separation of pyruvic acid，because pyruvic acid was unstable under the partial neutrality and high temperature. This study can thus provide an important theoretical reference for the separation and extraction of keto-acid.